Kumar-2011-Research-Methodology_-A-Step-by-Step-Guide-for-Beginners

Glossary 395
visible characteristic of interest, such as gender or race, of the study population. The sample is
selected from a location convenient to you as a researcher, and whenever a person with this
visible relevant characteristic is seen, that person is asked to participate in the study. The process
continues until you have been able to contact the required number of respondents (quota).
Random design: In a random design, the study population groups as well as the experimental
treatments are not predetermined but randomly assigned to become control or experimental
groups. Random assignment in experiments means that any individual or unit of the study
population has an equal and independent chance of becoming a part of the experimental or
control group or, in the case of multiple treatment modalities, any treatment has an equal and
independent chance of being assigned to any of the population groups. It is important to note
that the concept of randomisation can be applied to any of the experimental designs.
Random sampling: For a design to be called random or probability sampling, it is imperative
that each element in the study population has an equal and independent chance of selection
in the sample. Equal implies that the probability of selection of each element in the study
population is the same. The concept of independence means that the choice of one element
is not dependent upon the choice of another element in the sampling.
Random variable: When collecting information from respondents, there are times when
the mood of a respondent or the wording of a question can affect the way a respondent replies.
There is no systematic pattern in terms of this change. Such shifts in responses are said to be
caused by random or chance variables.
Randomisation: In experimental and comparative studies, you often need to study two or
more groups of people. In forming these groups it is important that they are comparable with
respect to the dependent variable and other variables that affect it so that the effects of independent
and extraneous variables are uniform across groups. Randomisation is a process that
ensures that each and every person in a group is given an equal and independent chance of
being in any of the groups, thereby making groups comparable.
Ratio scale: A ratio scale has all the properties of nominal, ordinal and interval scales plus its
own property; the zero point of a ratio scale is fixed, which means it has a fixed starting point.
Therefore, it is an absolute scale. As the difference between the intervals is always measured
from a zero point, arithmetical operations can be performed on the scores.
Reactive effect: Sometimes the way a question is worded informs respondents of the existence
or prevalence of something that the study is trying to find out about as an outcome of
an intervention. This effect is known as reactive effect of the instrument
Recall error: Error that can be introduced in a response because of a respondent’s inability
to recall correctly its various aspects when replying.